package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import io.netty.util.internal.StringUtil;
import org.apache.ibatis.annotations.Param;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.StringUtils;

import javax.annotation.Resource;

import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;

    @Override
    public Result queryById(Long id) {
        //缓存穿透
        Shop shop = cacheClient.
                queryWithPassThrough(CACHE_SHOP_KEY, id, Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.MINUTES);

        //互斥锁缓存击穿
//        Shop shop = queryWithMutex(id);

        //逻辑过期,缓存击穿
//        Shop shop1 = cacheClient.queryWithLogicalExpire(CACHE_SHOP_KEY, LOCK_SHOP_KEY, id, Shop.class,
//                this::getById, 20L, TimeUnit.SECONDS);

        if (shop == null){
            return Result.fail("店铺不存在");
        }
        return Result.ok(shop);
    }


    /**
     * 缓存击穿互斥锁
     * @param id
     * @return
     */
    public Shop queryWithMutex(Long id){
        String key = CACHE_SHOP_KEY + id;
        //1.从redis查询商户缓存..使用的是string类型
        String shopJson = stringRedisTemplate.opsForValue().get(key);

        //2.判断缓存是否命中
        if (StrUtil.isNotBlank(shopJson)){
            //3.命中,返回商户信息
            return JSONUtil.toBean(shopJson, Shop.class);
        }
        //命中的是空值
        if(shopJson != null){
            return null;
        }

        //4.没有,根据id查询数据库
        //获取锁
        Shop shop = null;
        try {
            boolean lock = tryLock(LOCK_SHOP_KEY + id);
            //判断锁存在吗
            if (!lock){
                //不存在,休眠,重试
                Thread.sleep(50);
                queryWithMutex(id);
            }
            //存在,根据id查询数据库
            shop = getById(id);
            //模拟高并发
            Thread.sleep(200);
            //5.在数据库中是否存在
            if (shop == null){
                //写入空对象给Redis
                stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL, TimeUnit.MINUTES);
                return null;
            }

            //6.商户数据写入Redis
            stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),LOCK_SHOP_TTL, TimeUnit.MINUTES);

        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }finally {
            //释放锁
            unLock(LOCK_SHOP_KEY + id);
        }
        return shop;
    }

    /**
     * 获取互斥锁
     * @param key
     * @return
     */
    private boolean tryLock(String key){
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 50, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);
    }

    /**
     * 释放互斥锁
     * @param key
     */
    private void unLock(String key){
        stringRedisTemplate.delete(key);
    }

    /**
     * 存储数据到Redis,带有逻辑时间,做数据预热
     * @param id
     * @param expireSeconds
     */
    public void saveShop2Redis(Long id,Long expireSeconds){
        //1.查询数据库
        Shop shop = getById(id);

        //2.设置过期时间
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));

        //3.写入Redis
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id,JSONUtil.toJsonStr(redisData));
    }


    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id == null){
            return Result.fail("店铺ID不能为空");
        }
        //1,更新数据库
        updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY + id);
        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //判断是否需要根据坐标查询
        if (x == null || y == null) {
            //不需要查询坐标
            Page<Shop> page = query().eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            //返回
            return Result.ok(page.getRecords());
        }
        //计算分页参数
        int from = (current -1 ) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;
        //查询Redis,按照距离排序,分页,结果返回shopId , distance
        //geosearch g1 FROMLONLAT 116.397904 39.9009005 BYRADIUS 10 km WITHDIST
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo()
                .search(key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.
                                newGeoSearchArgs().newGeoSearchArgs().
                                includeDistance().limit(end)
                );
        if (results == null){
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if (list.size() <= from){
            return Result.ok(Collections.emptyList());
        }
        //解析出id
        List<Long> ids = new ArrayList<>(list.size());
        HashMap<String, Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result->{
            //获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            //获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr,distance);
        });
        //根据id查询shop
        String idStr = StrUtil.join(",",ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        //返回
        return Result.ok(shops);
    }
}
